Neuroimmunological and clinical studies in Neuropsychiatric Lupus Erythematosus (NPSLE)

Transcription

1 From THE DEPARTMENT OF CLINICAL NEUROSCIENCE Karolinska Institutet, Stockholm, Sweden Neuroimmunological and clinical studies in Neuropsychiatric Lupus Erythematosus (NPSLE) Liisa Hopia Stockholm 2016

2 All previously published papers were reproduced with permission from the publisher. Published by Karolinska Institutet. Printed by E-PRINT AB Liisa Hopia, 2016 ISBN

3 Neuroimmunological and clinical studies in Neuropsychiatric Lupus Erythematosus (NPSLE) THESIS FOR DOCTORAL DEGREE (Ph.D.) By Liisa Hopia Principal Supervisor: Associate Professor Magnus Andersson Karolinska Institutet Department of Clinical Neuroscience Division of Neurology Co-supervisor(s): Professor Elisabet Svenungsson Karolinska Institutet Department of Medicine Division of Rheumatology Professor Fredrik Piehl Karolinska Institutet Department of Clinical Neuroscience Division of Neurology Opponent: Professor Ann-Marie Landtblom Uppsala University Department of Neuroscience Division of Neurology Examination Board: Professor Magnus Vrethem Linköping University Department of Clinical and Experimental Medicine Division of Neuro and Inflammation Sciences Professor Miia Kivipelto Karolinska Institutet Department of Neurobiology, Care Sciences and Society Division of Neurogeriatrics Associate Professor Per Larsson Karolinska Institutet Department of Medicine Division of Rheumatology

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5 To Ida and Kjell

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7 ABSTRACT Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with many organ manifestations and characteristic immunological abnormities including a large set of autoantibodies with affinity for nuclear and membrane components. Autoantibodies form immune complexes, which cause inflammation and tissue damage in affected organs. Neuropsychiatric symptoms in SLE (NPSLE) are common, but clinically we lack a systemic strategy/protocol to follow-up or investigate these patients. Symptoms are heterogeneous, including both central and peripheral nervous system manifestations. Several cytokines and biomarkers as well as risk factors for NPSLE have been associated with specific manifestations. Especially symptoms of central nervous system origin often contribute to serious clinical outcomes. The overall aim of this thesis was to provide a deeper understanding of NPSLE regarding clinical manifestations, to investigate the performance of potential new biomarkers and possible consequences that may be result from treatment with several immunosuppressive medications. Furthermore, to investigate two of the most common symptoms, stroke and seizures/epilepsy in SLE. In study I, we analyzed whether the activity of the cytokines APRIL and BAFF was enhanced in the systemic and/or the intrathecal compartments in NPSLE patients, as compared to healthy and multiple sclerosis (MS) controls. We also studied the relationship between APRIL/BAFF and fatigue in NPSLE. Levels of APRIL in the intrathecal compartment were significant higher. Fatigue correlated to higher APRIL levels in NPSLE. In study II, plasma and cerebrospinal fluid from NPSLE patients treated with several immunomodulatory medications and controls, were investigated for possible detectable John Cunningham virus (JCV) DNA occurrence. None of these samples showed detectable JCV levels. In study III, we investigated the distribution of ischemic stroke subtypes in SLE patients, and classifying them according the system Trial of Org in Acute stroke Treatment (TOAST) with possible association with STAT4 and HLA-DRBI risk genotypes. The anti-phospholipid Syndrome (APS) and cardiovascular genes (CE) play important roles in ischemic stroke. Patients with stroke in APS/other determined etiology (OE) were also younger compared with other subgroups. The STAT4 genotype associated specifically to ischemic stroke in both APS/OE and CE subtypes.

8 In study IV, we report that the prevalence of classified seizures and epilepsy in SLE is 11.5%, and the majority of defined epilepsy occurs as a focal epilepsy. APS was more common in patients with epilepsy compared to epilepsy-free SLE patients with or without NPSLE. Cerebrovascular disease was highly significantly more common. In 50% of patients with epilepsy no etiology other than SLE was detected. In conclusion, we have confirmed the importance of cytokines APRIL/BAFF in SLE, also detected in NPSLE in CSF. JCV DNA levels were not detectable in plasma or cerebrospinal fluid for the patients investigated in this study. Furthermore, patients with ischemic stroke seem to have association with APS or CE occurrence. Patients with defined epilepsy in SLE had mostly focal seizures. Cerebrovascular disease is common, and for about half the epilepsy cases we cannot determine any other etiology than autoimmune disease, SLE. Collectively, these findings support the notion of a multifaceted involvement of the nervous system in SLE. ISBN

9 LIST OF PUBLICATIONS This thesis is based on the following original papers, which will be referred to in the text by their Roman numerals: I. L Hopia, M Thangarajh, M Khademi, A Laveskog, E Wallström, E Svenungsson, M Andersson. Cerebrospinal fluid levels of a proliferation-inducing ligand (APRIL) are increased in patients with neuropsychiatric systemic lupus erythematosus. Scand J Rheumatol (2011);40: II. E Iacobaeus, L Hopia, M Khademi, M Lundén, A-L Hammarin, E Svenungsson, M Andersson. Analysis of JC virus DNA in NPSLE patients treated with different immunomodulatory agents. Lupus (2013) 22, III. L Hopia, A Laveskog, A Jönsen, D Leonard, J T Gustafsson, I Gunnarsson, A Zickert, G Nordmark, A A. Bengtsson, K Elvin, L Padyukov, J K. Sandling, A-C Syvänen, L Rönnblom, M Andersson, E Svenungsson. Ischemic stroke in Systemic Lupus Erythematosus-Distribution of sub-types and association with STAT4 and HLA-DRB1 genes. Manuscript. IV. L Hopia, M Andersson, E Svenungsson, M Khademi, F Piehl, T Tomson. Epilepsy in Systemic lupus erythematosus: Prevalence and risk factors. Submitted.

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11 CONTENTS 1. SYSTEMIC LUPUS ERYTHEMATOSUS BACKGROUND CLINICAL FEATURES AND CLASSIFICATIONS OF SLE AUTOANTIBODIES IN SLE Anti-phospholipid antibodies (apl) and the APS syndrome THE IMMUNE SYSTEM The complement system The immune system and SLE B-cell efficiency- BAFF and APRIL Genetics CLINICAL SYMPTOMS IN NPSLE CEREBROVASCULAR DISEASE AND SLE Stroke Subtypes according to TOAST Large artery atherosclerosis (LA) Cardio-embolism (CE) Small artery occlusion (SAO)/lacunar Acute stroke of other determined etiology (OE) Stroke of undetermined etiology (UE) EPILEPSY, SEIZURES AND NPSLE Definition of epilepsy Definition of seizures JC-VIRUS, PML and SLE AIMS OF THE THESIS MATERIALS AND METHODS SUBJECTS AND STUDY DESIGN (I-IV) CLINICAL INSTRUMENTS QUESTIONNAIRES LABORATORY MEASUREMENTS Cerebral fluid and routine laboratory parameters Autoantibodies (I-IV) Quantification of APRIL and BAFF by ELISA and PCR JCV PCR analysis..25

12 Genotyping Statistical analyses RESULTS AND DISCUSSION Paper I Paper II Paper III Paper IV GENERAL DISCUSSION FUTURE DIRECTIONS CONCLUSIONS ACKNOWLEDGEMENTS REFERENCES.. 40

13 LIST OF ABBREVIATIONS Ab ACR ANA Anti-dsDNA Anti-La/SSB Anti-Ro/SSA Anti-RNP Anti-ribo P Anti-Sm aß₂gpi acl apl APC APS APRIL BAFF BBB Bly S C CE CNS CSF CT EEG ELISA EP FSS GAPDH HLA IC IFN Ig IHD IL ILEA IRF JCV LA LAA LE MAC Antibody American College of Rheumatology Antinuclear Antibodies Antibodies to double stranded DNA Anti-Sjögrens Syndrome antigen B Antibodies Anti-Sjögrens Syndrome antigen A Antibodies Anti-Ribonuclearprotein Antibodies Anti-Ribosomal P Antibodies Anti-Smith Antibodies Anti-ß₂ Glycoprotein I Antibodies Cardiolipin Antibodies Antiphospholipid Antibodies Antigen Presenting Cell Antiphospholipid Syndrome A-proliferation-Inducing Ligand B-cell Activation Factor Blood Brain Barrier B lymphocyte Surface Complement component Cardio-embolism Central nervous system Cerebrospinal fluid Computer tomography Electroencephalogram Enzyme-linked immunosorbent assay Epilepsy Fatigue Severity Scale Glyceraldehyde-3-phosphate dehydrogenase Human leucocyte antigen Immune complex Interferon Immunoglobulin Ischemic heart disease Interleukin International League against Epilepsy Interferon regulatory factor John Cunningham virus Lupus anticoagulant Large artery atherosclerosis Lupus erythematosus cell Membrane-attack complex

14 MRI Magnetic resonance imaging mrna Messenger RNA MS Multiple sclerosis NMDA N-methyl D-aspartate NK Natural killer NP Neuropsychiatric NPSLE Neuropsychiatric Systemic Lupus Erythematosus OE Other determined etiology (TOAST) OND Other neurological diseases PB Peripheral Blood PBMC Peripheral Blood Mononuclear Cells PCR Polymerase Chain Reaction PET Positron emission tomography PML Progressive Multifocal Leukoencephalopathy PNS Peripheral nervous system PRES Posterior reversible encephalopathy syndrome RR-MS Relapsing-remitting MS SAO Small artery occlusion SLE Systemic Lupus Erythematosus SLICC Systemic Lupus International Collaborating Clinics SNP Single Nucleotide Polymorphism SSP PCR Sequence-specific primer PCR STAT4 Signal transducer and activator of transcription 4 TACI Transmembrane activator TGFß Transforming growth factor-ß TIA Transitory ischemic attack TNF Tumor Necrosis Factor TOAST Trial of Org in Acute Stroke Treatment UE Undetermined etiology (TOAST) WHO World Health Organization

15 1. SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) 1.1. BACKGROUND Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with several organ manifestations and characteristic immunological abnormalities including a large set of autoantibodies (1-4). SLE mainly affects females with peak incidence between the ages of 15 to 40 and a male-to-female ratio of approximately 1: 9. However, SLE can also be diagnosed in young children and in the older population. The worldwide prevalence is estimated to be 3-207/ and in Sweden 46-85/ (5-7). The prevalence varies with race, ethnicity and socioeconomic status (5, 8-9). In order to classify as SLE the patient needs to fulfil four or more of the eleven criteria, based on the 1982 American College of Rheumatology (ACR) revised criteria for classification (10) that include 9 clinical and 2 immunological criteria. However, these criteria are made to classify patients in clinical studies. There are presently no diagnostic criteria and thus doctors can diagnose SLE even if the criteria are not fulfilled. Neurological manifestations and neuropsychiatric symptoms are common and occur in approximately 50-90%, depending on definition. In general, neurological presentations are very heterogeneous and they include 19 Neuropsychiatric Lupus Erythematosus (NPSLE) syndromes as defined by the ACR. These syndromes affect both the central (CNS) and peripheral nervous systems (PNS) and they also include psychiatric manifestations (11, 12). One of the original 11 ACR classification criteria is neurological and includes the symptoms epilepsy or psychosis. In 2012 the Systemic Lupus International Collaborating Clinics (SLICC) group proposed new classification criteria for SLE. These criteria have been extended with regard to NPSLE symptoms and include mononeuritis multiplex, myelitis, peripheral or cranial neuropathy and acute confusional states in addition to seizures and psychosis (13). Involvement of the central nervous system (CNS) is generally associated with poor prognosis in SLE (14-16). 1

16 1.2. CLINICAL FEATURES AND CLASSIFICATION OF SLE The clinical manifestations are heterogeneous and presentations may differ during the course of SLE. In general, the disease course can be described as relapsing-remitting, chronic active or as a quiescent chronic active condition (17). The most frequently affected organs at any time are joints (arthritis/arthralgia) and skin with photosensitivity, discoid lupus or malar rash. Further, 30-40% are affected with nephritis, 40% with serositis presenting either as pericarditis or pleuritis. Symptoms of SLE can be mild and limited to only a few organs, but disease flares can also be aggressive with involvement of several organs simultaneously. According to the revised criteria for SLE by Tan 1982, 11 criteria are used to define SLE. There are 9 clinical or routine laboratory criteria: malar rash, discoid rash, photosensitivity, oral ulcers, arthritis, serositis, renal disorder, neurological disorder or hematologic disorder, immunologic disorder or detectable antinuclear antibodies (ANA). Additionally, there are two immunological criteria including: 1) antibodies to double stranded DNA (anti-dsdna) or anti-smith (anti-sm) antibodies, positive lupus erythematosus (LE) cell staining or 2) an abnormal titer of ANA by immunofluorescence. A definite SLE classification can thus be established if the patient has presented at least four of the eleven criteria. Table 1. Antibodies to double stranded DNA Severe fatigue is a common and disabling symptom in SLE. It has also been reported by patients with chronic inflammatory rheumatic disease, as well as for patients with multiple sclerosis (MS) (18, 19). However, it is not defined by the ACR as a clinical feature in SLE or in NPSLE. 2

17 Table 1. The 1982 revised criteria for classification of systemic lupus erythematosus* Criteria Definition 1. Malar rash Fixed erythema, flat or raised, over the malar eminences, tending to spare the nasolabial folds 2. Discoid rash Erythematous raised patches with adherent keratotic scaling and follicular plugging; atrophic scarring may occur in older lesions 3. Photosensitivity Skin rash as a result of unusual reaction to sunlight, by patient history or physician observation 4. Oral ulcers Oral or nasopharyngeal ulceration, usually painless, observed by a physician 5. Arthritis Non-erosive arthritis involving 2 or more peripheral joints, characterized by tenderness, swelling, or effusion 6. Serositis Pleuritis - convincing history of pleuritic pain or rub heard by a physician or evidence of pleural effusion or Pericarditis - documented by ECG or rub or evidence of pericardial effusion 7. Renal disorder Persistent proteinuria greater than 0.5 grams per day or greater than 3+ if quantitation not performed. Cellular casts - may be red cell, hemoglobin, granular, tubular, or mixed 8. Neurological disorder 9. Hematologic disorder 10. Immunologic disorder 11. Antinuclear antibody (ANA) Seizures - in the absence of offending drugs or known metabolic derangements, e.g., uremia, ketoacidosis, or electrolyte imbalance Psychosis - in the absence of offending drugs or known metabolic derangements, e.g., uremia, ketoacidosis, or electrolyte imbalance Hemolytic anemia-with reticulocytosis. Leukopenia-less than 4,000/mm 3 total on 2 or more occasions OR Lymphopenia-less than 1,500/mm 3 on 2 or more occasions or Thrombocytopenialess than 100,000/mm 3 in the absence of offending drugs Positive LE cell preparation Anti-DNA: antibody to native DNA in abnormal titer Anti-Sm: presence of antibody to Sm nuclear antigen False positive serologic test for syphilis known to be positive for at least 6 months and confirmed by Treponema pallidum immobilization or fluorescent treponemal antibody absorption test An abnormal titer of antinuclear antibody An abnormal titer of antinuclear antibody by immunofluorescence or an equivalent assay at any point in time and in the absence of drugs known to be associated with drug-induced lupus syndrome * The proposed classification is based on 11 criteria. For the purpose of identifying patients in clinical studies, a person shall be said to have systemic lupus erythematosus if any 4 or more of the 11 criteria are present, serially or simultaneously, during any interval of observation (10). 3

18 1.3. AUTOANTIBODIES IN SLE Autoantibodies play a central role in SLE, which has been proposed to be the autoimmune condition with the largest number (>100) of detectable autoantibodies. These include autoantibodies that target nuclear antigens, cytoplasmic antigens, cell membrane antigens, phospholipid-associated antigens, blood cells, endothelial cells, nervous system antigens, plasma proteins, matrix proteins and miscellaneous other antigens. The targets of these autoantibodies, the autoantigen IC properties, autoantibody frequencies, as well as clinical associations, and correlation with disease activity have previously been described (20, 21). Anti-nuclear antibodies (ANA) are present in 95-99% of SLE patients and antibodies against double-stranded DNA (anti-dsdna) are present at any time in about 50-70%, and they have been shown to increase just prior to SLE onset and they are often positive in nephritis patients (22). Certain autoantibodies have been connected with clinical features of SLE. For example, anti-ribosomal P (anti-ribo P) antibodies have been linked with psychosis (23) and anti-smith (anti-sm) antibodies with milder renal and CNS disease, as well as with relapse of SLE. Other antibodies such as Sjögrens syndrome (Antigen- A and B) -associated anti- Ro (SSA), and anti-la/ssb are associated with secondary Sjögren s syndrome, lymphopenia and a milder disease course while anti-c1q are associated with nephritis. Furthermore anti-histone antibodies have been reported in some cases of drug-induced lupus (23) Antiphospholipid antibodies (apl) and APS syndrome The presence of apl, a heterogeneous group of autoantibodies are associated with increased risks of thrombotic events in SLE and in the general population. These antibodies are thus more commonly detected in patients with a variety of vascular events. A large international study based on 120 full-text papers, though the majority were published before 1 reported the following frequencies: 13.5% in patients with stroke, 11% in myocardial infarction (MI), 9.5% in deep venous thrombosis (DVT) and 6% among women presenting with pregnancy morbidity (24). The antiphospholipid antibody syndrome (APS) is defined by the presence of antibodies against cardiolipin of IgG or IgM isotypes (IgG acl, IgM acl) or antibodies 4

19 against phospholipid binding cofactor ß₂glycoprotein-I (GPI) of IgG or IgM isotypes (IgG anti-ß₂gpi, IgM anti-ß₂gpi) or positivity in the functional lupus anticoagulant (LA) test. One or more thrombotic (venous, arterial-or small vessel) event in any tissue or organ, and/or pregnancy-related morbidity are needed (24-26) to classify for the clinical APS criterion. At least one clinical criterion as well as a minimum of two positive tests at least 12 weeks apart are required for a confirmed APS diagnosis (27). APS was first described in patients with SLE, i.e. secondary APS, but it is now regarded as a separate entity. When APS occurs in the absence of other autoimmune disorders it is referred to as (primary APS). The definition is the same for primary and secondary APS THE IMMUNE SYSTEM A vital function of the immune system is to defend the body from invasion by bacteria, viruses and parasites, but it is also involved in other important functions such as repair after tissue injury and cancer cell surveillance. At a very basic level, the immune system can be subdivided into two parts; natural/innate and specific/adaptive immunity. The innate system consists of mechanical barriers such as skin and mucosa, phagocytic cells of the myelomonocytic lineage (macrophages, dendritic cell, neutrophils and natural killer (NK) cells) and serum constituents such as complement proteins and cytokines. The innate immune system acts by recruiting immune cells to sites of infection or damage and producing cytokines and other mediators of inflammation. Activation of antigen presenting cells (APCs) and the complement cascade will also act as a bridge to the adaptive arm of the immune system. The adaptive immune system consists mainly of T and B lymphocytes, which represent the two major subdivisions, humoral and cell-mediated immunity, respectively. The humoral part consists of B cells that have antigen presenting properties and produce antibodies. Further maturation of B cells will lead to long-lived plasma cells, which are the main source of antibodies/immunoglobulin (Ig) molecules. The cell-mediated arm comprises T cells with cytotoxic or regulatory capacity. T lymphocytes can be further divided into major subsets T-helper (CD4 + ) and cytotoxic (CD8 + ) cells. However, additional T cell populations include also other types of 5

20 cells, such as regulatory T cells that are important for regulation of adaptive immune responses. Based on the types of cytokines they produce, CD4 + T-helper cells can be classified into additional phenotypes including T helper 1 (Th1) and T helper 2 (Th2), T helper 17 (Th17) and T regulatory cells (Treg). Differentiation into either of these two phenotypes leads to preferential secretion of certain signature cytokines. Th1 cells secrete interferon-γ (IFN-γ), interleukin 2 (IL-2), interleukin 12 (IL-12), and tumor necrosis factor-α (TNF-α), which promote cell-mediated responses. Interleukins 4, 5, 9 and 10 (IL-4, 5, 9, 10) instead are secreted by Th-2 cells and promote humoral or allergic responses. Th17 cells secrete interleukins-17, -21 and -22 (IL-17, -21, -22) and are believed to be of importance for mediating tissue inflammation including autoimmune disease. Tregs play an important role for mediation of immune tolerance and controlling immune responses so that they do not go out of control, which is mediated by secretion of cytokines such as interleukin -10 (IL-10) and transforming growth factor-ß (TGFß). The adaptive immune system is different from the innate immune system in that it can learn to recognize (adapt) and mount a very strong immune response against distinct antigens. Unfortunately, antigen recognition may cross-react with self-peptides or other altered selfmolecules and thus create the basis for autoimmune diseases The complement system The complement system has a protective function in our immune system. It consists of plasma proteins and the activation of one component leads to a cascade of reactions. The classical, mannose-binding lectin and alternative complement pathways make up this system, each of them utilizing specific chemical functions. All lead to formations of enzymatic complexes (C3 and C5) and further reactions that attract white blood cells and form a cytotoxic membrane- attack complex (MAC). The classical pathway is mainly interactive with complement component C1q and IgG and IgM antibodies. The complement system has many biological functions. It facilitates phagocytosis and clearance of immune complexes (ICs) and dying cells, and it also attracts inflammatory cells to sites of complement activation. Typical findings in SLE are low serum concentrations of complement C1q, C3 and C4, mainly during flares (28). Furthermore, genetic C1q deficiency is a rare but strong risk factor for SLE. Individuals with genetic complement deficiencies, e.g. of C1q, C2 and C4, are 6

21 strongly predisposed to develop SLE (29). These findings may contribute to our understanding of up-regulation of the type I IFN system seen in SLE patients (28) The immune system and SLE In SLE a central immunologic disturbance is the excessive production of autoantibodies that induce damage via several mechanisms. Autoantibodies target self-molecules that are present in the nucleus, the cytoplasm and on cell surfaces. Antibodies together with their antigens and complement proteins form immune complexes, which are trapped, or possibly formed in tissues, where they can activate complement and cause inflammation and damage. The inflammatory state leads to further immune cell abnormalities and dysregulation that involves B cells, T cells and cells of the monocyte lineage. Both innate and adaptive immunity are highly involved. Increased systemic inflammation can be detected in patients with SLE. However, classical measures of inflammations, such as C-reactive protein are not good markers of SLE disease activity. Rather, high levels of multiple pro-inflammatory cytokines in peripheral blood have been reported in active SLE disease. Type I interferons (IFN), including interferon-α (IFN- α) have been demonstrated to correlate both with disease activity and severity, and this is a key cytokine in lupus. Type I IFNs have also being associated with vascular disease in SLE (30-32). TNF-α is another cytokine that together with its soluble receptors 1 and 2 reflects disease activity (33,134). The complement system is also important in SLE, where peripheral blood levels of several complement proteins are depressed due to consumption during more active disease. This is especially common during active nephritis (29, 34) B-cell efficiency- BAFF and APRIL B cells require signals from several sources for their maturation from precursor cells and for further developing to effector cells. Two closely related cytokines belonging to the tumor necrosis factor (TNF) family are involved in various human autoimmune conditions (35). High levels of both B-cell activating factor (BAFF) and a-proliferation-inducing ligand (APRIL) have been demonstrated in patients with SLE and in other autoimmune conditions such as rheumatoid arthritis and Sjögren s syndrome (36-38). 7

22 BAFF, also known as TALL-1, THANK, Bly S, ztnf4 and TNFSF13, and APRIL, also known as TRDL-1, are both linked to B-cell survival, Ig isotype switching, and B-cell antigen presentation (39-41). They are present in the circulation as soluble trimeric ligands, but BAFF can also be detected as a membrane-bound protein (40). Both of these cytokines bind to two receptors, B-cell maturation antigen (BCMA) and transmembrane activator (TACI), BAFF also separately binds to BAFF-R, and thereby regulates B-cell survival. Figure 1. Figure 1. BAFF and APRIL were highlighted at the time of our study, since clinical trials of a new human anti-soluble BAFF monoclonal antibody, Belimimab, were ongoing. Efficacy in lupus patients has since been demonstrated. Belimimab is now registered for treatment of SLE and is has been shown to reduce both disease activity and fatigue (42, 43). 8

23 Genetics More than 60 genetic variants have been linked to risk of SLE. The most strongly associated genetic region is the HLA region, located on chromosome 6, which contains many genes of importance for the immune system and for autoimmunity including those encoding for the major histocompatibility class I and class II chains. Some of the identified SLE susceptibility genes located elsewhere in the genome are linked to interferon signaling, such as interferon regulatory factor 5 (IRF5) and signal transducer and activator of transcription 4 (STAT4), both of which have been repeatedly confirmed to be associated with SLE (44-46). Additionally, although less common, persons with genetic deficiencies of complement proteins involved in the classical complement activation pathway are prone to develop SLE (29, 47). 9

24 2. CLINICAL SYMPTOMS IN NPSLE Neurological symptoms in SLE are common and may have multiple causes. Of the 19 NPSLE case definitions by ACR (11) 12 are syndromes or manifestations from the CNS: aseptic meningitis, cerebrovascular disease, demyelinating syndrome, headache, movement disorder, myelopathy, seizure disorder, acute confusional state, anxiety disorder, cognitive dysfunction, mood disorder and psychosis, while 7 involve the PNS; Guillain-Barré, autonomic disorder, mononeuropathy, myasthenia gravis, cranial neuropathy, plexopathy and polyneuropathy. PNS symptoms are less common than CNS involvements. Table 2. Involvement of the CNS in SLE is potentially severe, but still in most cases a treatable condition (48). Unfortunately, there is a lack of validated biomarkers for CNS involvement and neuroradiological findings may be non-specific. The fact that opportunistic infections, sometimes a consequence of immunosuppression, may mimic NPSLE symptoms further complicates the diagnostic work-up (49-53). Several cytokines have been suggested to be increased during fatigue in SLE, but studies so far have not provided evidence for association to disease activity or other markers of disease or inflammation (54). Table NPSLE syndromes as defined by the American College of Rheumatology Central Nervous System Aseptic meningitis Cerebrovascular disease Demyelinating syndrome Headache (including migraine and idiopathic intracranial hypertension) Movement disorder (chorea) Myelopathy Seizure disorder Acute confusional state Anxiety disorder Cognitive dysfunction Mood disorder Peripheral Nervous System Acute inflammatory demyelinating polyradiculopathy (Guillain-Barré) Autonomic disorder Mononeuropathy, single or multiplex Myasthenia gravis Cranial neuropathy Plexopathy Polyneuropathy Extensive efforts have been made to better understand the underlying pathological mechanisms for neurological symptoms in NPSLE, and several candidate biomarkers have 10

25 been suggested (55). However, many issues remain to be resolved and it is likely that several mechanistic pathways are involved and probably overlap. Neuropathological studies, by necessity performed in severe and dramatic clinical manifestations of CNS involvement, often demonstrate ischemic changes in small vessels such as cortical microinfarctions and a general vasculopathy with degenerative or proliferative changes generally (23). Reductions in cerebral and corpus callosum volumes and atrophy have been associated with disease duration and the history of CNS involvement and cognitive impairment. Furthermore, the total corticosteroid dose and the presence of apl have not shown association to brain atrophy (56, 57). Macroscopic infarctions are less common. Embolism often arises from the heart, due to heart valve involvement, usually more discrete but sometimes in accordance with Libman-Sacks endocarditis (58-61). Both inflammatory infiltrates and destruction of blood vessel walls may occur, but necrosis indicative of vasculitis is rarely observed. NPSLE is associated with systemic-and brain-specific antibodies (62). A recent metaanalysis of serum and CSF autoantibodies by Ho et al (51) reported that NPSLE patients, mainly those with CNS symptoms, tend to have higher levels of apl including acl and LA, as well as, anti-ribo P abs and anti-neuronal abs compared with SLE patients without neuropsychiatric symptoms. This was especially evident for patients with psychiatric conditions, cognitive impairment, cerebrovascular disease and seizures. Additionally, brainspecific abs such as anti-ganglioside, anti-glial fibrillary acidic protein, anti-lymphocytotoxic and anti-nmda as well as anti-neuronal abs were mainly encountered in neuropsychiatric conditions. Neuropathy, psychosis and seizures have been reported to associate with antimicrotubule protein 2 antibodies leading to changes in neuron morphology (63). One possible mechanism for vascular occlusion and injury by pathogenic antibodies is a disrupted blood brain barrier (64). Antibodies can mediate neurological injury by reacting against neuronal, astroglial or endothelial cells (23, 65-67). According to a more recent hypothesis, subtypes of N-methyl D-aspartate (NMDA) receptors may become targets for cross-reactive anti-dna antibodies and the neuronal excitations, by way of excessive activation, may lead to neurocognitive disturbances and eventually to brain atrophy (67-70). apl occur in 30-40% of SLE patients (71) and are associated with thrombotic and/or obstetric manifestations and seizures (30, 64, 72, 73). Furthermore, interferon-α (IFN-α) and other type I interferons have been demonstrated to correlate both with disease activity and severity and also have strong associations to vascular disease in SLE (22). Elevated levels of APRIL have also been reported in cerebrospinal fluid for SLE patients with neuropsychiatric symptoms as compared to controls (74). 11

26 Neuropsychiatric lupus erythematosus syndromes are often associated with global disease activity (75). Nonspecific cerebrospinal fluid (CSF) abnormalities are present in about 30% of patients, including elevated levels of monocytes, elevated protein levels or abnormalities in intrathecal production of immunoglobulins (76, 77). Levels of cytokines such as IL-6, -8 and -10 has been reported to be increased in the CSF of individuals with neurolupus compared with non-cns lupus (78). The electroencephalogram (EEG) changes in NPSLE patients are often nonspecific generalized slowing (48). Imaging with computed tomography (CT) may show evidence of cerebral infarction and hemorrhage, cortical micro-infarcts or vasculopathy and degenerative changes, and in chronic cases subcortical atrophy. Magnetic resonance imaging (MRI) is useful especially in patients with diffuse presentations. It reveals small infarcts in acute states, focal cerebral edema and detects myelitis better than CT. However, there are no MRI findings that are diagnostic of NPSLE (78, 79). Positron emission tomography (PET) has also been used to detect areas of disturbed cerebral circulation and metabolism (80). Neuropsychiatric manifestations are common in SLE and may present in the context of general disease activity or as isolated events. Patients often present with mixed neurologic and psychiatric manifestations. The prevalence of NP manifestations according to ACR case definitions is variable. Accordingly several studies report that from 14% to over 90% of SLE patients presenting with neurological or psychiatric symptoms at some time during their illness (78). A recent large international, multicenter prospective study reported that 40.3% of the patients had at least one clinical NP event and 17.4% were diagnosed with multiple events (81). Different results may be due to technical variations between the studies, study designs and selections of the patients, study populations and how the original information was obtained. However, the most common NPSLE symptom reported are related to CNS manifestations. Most frequent are intractable headaches 24% (82, 83) including mostly tension-type and/or migraine, cluster headache or pseudo tumor cerebri. The second most common manifestation is cerebrovascular disease 14.5%, including transitory ischemic attack, ischemic stroke, subarachnoid/intracranial hemorrhage and sinus thrombosis. Mood disorders with major depressive episodes, depressive features and with manic features are common. Cognitive disorder have been reported to occur in about 11% and seizures in 8.3%. Psychosis as well as anxiety disorders are fairly common symptoms. Manifestations from PNS are seen more seldom, except polyneuropathy and cranial neuropathy (82). According to a Finnish study at least one NPSLE syndrome was identified in 91% of SLE patients (84). Cognitive dysfunction was present in 81%, followed by headache in 54% and mood disorder 12

27 in 43%. Headache, cognitive dysfunction and psychiatric disorders followed by seizures are also reported as the most common NPSLE syndromes in other studies (12, 85) CEREBROVASCULAR DISEASE AND SLE Stroke is defined by rapid onset of focal neurological deficit due to infarction or hemorrhagic vascular event lasting more than 24 hours, being the second most common cause of death worldwide and most common cause of neurological disability (86-89). A populations-based stroke register study in European countries reported an annual stroke incidences of / with a median age of 73 years, higher rates of stroke being reported in eastern and lower rates in southern European countries (90), with an incidence of 144/ in Sweden (91). Early risk of stroke following a transitory ischemic attack (TIA) is high; the 7-day risk is 8-12% and 30 day risk 18%. Traditional well-established risk factors are: age >55 years and male gender, hypertension, smoking, diabetes mellitus, hypercholesterolemia, atrial fibrillation and myocardial infarction. A recent population-based meta-analysis by Holmqvist et al. (92) reported that individuals with SLE have a two-fold increased risk of ischemic stroke compared to the general population and that the relative risk of stroke was highest among individuals younger than 50 years of age. Another large meta-analysis performed with a wider clinical material of rheumatic diseases reported risk of any stroke to be particularly higher for patients with rheumatoid arthritis and systemic lupus erythematosus (93). In a large cross-sectional study from our group ischemic cerebrovascular disease occurred in 12% of Swedish SLE patients (44). The mean annual stroke incidence in another SLE cohort was 6.45/1000 patients where 90% had ischemic strokes and 10% hemorrhagic events. Furthermore, stroke occurred in 57% of SLE patients with a history of TIA (94, 95). High mortality 20-30% in SLE occurs due to cerebrovascular events. 13

28 Stroke subtypes according to TOAST The Trial of Org in Acute Stroke Treatment (TOAST) (96) criteria is the most commonly used for pathogenic classification of stroke cases. It is designed to classify ischemic strokes, and is mainly based on etiology, being defined for use in a multicenter clinical trial setting, TIA being excluded. Five major categories of the TOAST classification are as follows: large-artery atherosclerosis (LAA); cardio-embolism (CE); small artery occlusion (SAO); stroke of other determined cause (OC); and stroke of undetermined cause (UE). The sub-type definitions are based on risk factor profiles, clinical features, and results of diagnostic tests (97). A population-based prospective study for incidence, recurrence and long-time survival rates of ischemic stroke in European populations according to TOAST criteria, reported the following distributions of stroke sub-types: CE 27%, SAO 23%, LAA 13%, OE 2% and UE 35% (97, 98). Another previous prospective study among SLE patients reported that the LAA was most common sub-type, in 45%, SAO occurred in 39% and CE in 9% followed by 7% of UE (131) Large artery atherosclerosis (LAA) Patients in this category should have a history of large-artery atherosclerosis, supported by clinical and brain imaging findings. Typically findings for these patients include a significant (>50%) stenosis or occlusion of a major brain artery or branch cortical artery or in an extracranial artery, and history of transient ischemic attacks (TIAs) in the same vascular territory with symptoms of cerebral cortical impairment. Ischemic lesions located in cerebral cortex, cerebellum, brainstem or in subcortical areas should be greater than 1.5 cm in diameter as visualized by CT or MRI Cardio-embolism (CE) The TOAST classification includes both high- and medium risk sources for cardio-embolism causes of an arterial occlusion and stroke. Clinical evidence of previous TIA or stroke in 14

29 more than one vascular territory or systemic embolism supports a clinical diagnosis of cardiogenic stroke. The patients have similar clinical and brain imaging findings as in the LAA group Small artery occlusion (SAO)/lacunar Patients in this group should have a normal CT/MRI examination or a relevant brainstem or subcortical hemispheric lesion with a diameter of less than 1.5 cm. Clinical diagnosis is also supported if the patient has a history of diabetes mellitus or hypertension Acute stroke of other determined etiology (OE) Non-atherosclerotic vasculopathies, hypercoagulable states and hematologic disorder are all represented in this category. According to TOAST this subgroup includes patients with rare causes of stroke. Patients should have clinical and CT or MRI findings of an acute ischemic stroke, regardless of the size or location. Diagnostic studies such as blood tests or arteriography should reveal one of these unusual causes of stroke. Cardiac sources of embolism and large artery atherosclerosis should be excluded. In our study we included all patients with APS and SLE, as a known multisystem disease and without evidence of these other conditions, in this sub-group Stroke of undetermined etiology (UE) This category includes the cases of unclear etiology despite an extensive evaluation or insufficient evaluation. The patients with two or more potential causes of stroke, where the physician is unable to make a final diagnosis are included in this group. 15

30 2.2. EPILEPSY, SEIZURES AND NPSLE Seizures are a well-recognized complication (85, 99) in SLE and are suggested to be a result of a combination of immune, vascular, metabolic and inflammatory mechanisms. Furthermore, the generalized seizures have been associated with elevated levels of IgG, oligoclonal bands, and increased cytokine production, also with enhanced titers of antineuronal antibodies (85, 100). Seizures have also been reported to be an early CNS manifestation (48, 101) in SLE and are in some studies also diagnosed as an isolated epilepsy (102). Variable frequencies and prevalence of seizure disorder are described, from 6 51% of adults and pediatric SLE patients (12, 82, 84, ) and is reported to be more frequent in children. Furthermore, unprovoked seizure in MS and SLE in population-based case-control studies reported increased risks in both of these conditions (107) Definition of epilepsy Epilepsy has been defined as a condition characterized by recurrent (two or more) epileptic seizures, unprovoked by any immediate identified cause in the 1993 International League Against Epilepsy (ILAE) Commissions report (108). The new conceptual ILAE from 2005 defines epilepsy as a disorder of the brain characterized by an enduring predisposition to generate epileptic seizures and by the neurobiological, cognitive, psychological and social consequences of this condition (109). As follow-up of this conceptual definition, the ILEA in 2014 published a report describing a practical clinical definition of epilepsy. In accordance to this, epilepsy is a disease of the brain that can be defined by any of the following conditions: (I) At least two unprovoked (or reflex) seizures occurring >24 h apart; (II) one unprovoked (or reflex) seizure and a probability of further seizures similar to the general recurrence risk (at least 60%) after two unprovoked seizures, occurring over the next 10 years; (III) diagnosis of an epilepsy syndrome (110, 111). Important for an epilepsy diagnosis is the distinction between unprovoked and provoked (acute symptomatic) seizures. A seizure provoked by a transient factor acting on an otherwise normal brain to temporarily lower the seizure threshold does not qualify for epilepsy, even if recurrent. Epileptic seizures occurring in conjunction with an SLE flare or a 16

31 metabolic derangement, are hence considered to be acute symptomatic and do not count as epilepsy. Epilepsy is considered to be resolved for individuals who either had an agedependent epilepsy syndrome, but are now past the applicable age or who have remained seizure-free for the last 10 years and off anti-seizure medicines for at least the last 5 years. ˋResolvedˊ is not necessarily identical to the conventional view of ˋremissionˊ or ˋcureˊ Definitions of seizures The definition and classification of seizures differs from that of epilepsy. A seizure is a transient occurrence of signs and/or symptoms of epilepsy due to abnormal excessive or synchronous neuronal activity in the brain (109). The seizure presentations depend on the location of onset in the brain and the pattern of propagation. The seizures can further affect sensory, memory, cognition, or behavior. Somatosensory, auditory, visual, olfactory, gustatory and vestibular sensory and also more complex internal sensations that can be presented (109). Seizures are classified as either focal or generalized, the former focal involving a localized part of the brain whereas generalized seizures rapidly involve the whole of both brain hemispheres from the onset. Secondary generalized describes the condition in which a focal seizure from a primary focus in some part of brain spreads into both hemispheres and becomes generalized. This classification does not describe the etiology, prognosis or pathophysiology for causes of seizures or epilepsy JC VIRUS, PML and SLE Progressive multifocal leukoencephalopathy (PML) is a rare but often fatal demyelinating disease of the CNS caused by the polyomavirus John Cunningham virus (JCV), with a mean survival time of 3-6 months (112). Due to immunosuppression the virus can reactivate and enter the brain and infect oligodendrocytes, causing a fulminate infection, demyelination, PML and further pathological destruction of the brain (113). (Figures 2 and 3). The primary infection occurs in up to 80% of the individuals, usually asymptomatic and after infection the virus tend to stay latent in the kidneys, bone marrow and lymphoid tissues and glial cells. Both T- and B cell effector functions are required to prevent viral reactivation (114). 17

32 The incidence of PML in autoimmune diseases, including rheumatic diseases and mostly in patients with systemic lupus erythematosus has increased as a consequence of use of more potent immunosuppressive drugs such as biologics (rituximab, natalizumab, infliximab and efalizumab), methotrexate, azathioprine, cyclophosphamide and mycophenolate mofetil and even with a minimum of immunomodulatory treatments ( ). Figure 2. Pathology of progressive multifocal leukoencephalopathy (PML). (113) A. PML lesions affecting the superficial subcortical gray-white matter junction in the cerebral hemisphere. Multifocal punctate demyelinating lesions in subcortical white matter. B. Microscopic demyelinated lesion in the white matter immediately subcortical. The cortex and neuronal cell bodies are in the left of the picture. Figure 3. Brain MR imaging of PML lesions associated with lupus and methotrexate overdose (119) 18

33 SLE/NPSLE is a complex condition with several immune aberrations. In our studies included in this thesis I have chosen to concentrate on some important clinical manifestations: stroke, epilepsy, PML, biomarkers and fatigue. 19

34 3. AIMS OF THE THESIS The overall aim of this thesis was to provide a deeper understanding of NPSLE regarding clinical manifestations, potential biomarkers and pathophysiology. The specific aims of this thesis were as follows: 1 To study whether APRIL/BAFF activity is enhanced in the systemic and/or the intrathecal compartments in neuropsychiatric SLE (NPSLE) patients compared to healthy controls, and to study the relationship between APRIL/BAFF and fatigue in neuropsychiatric SLE 2 To analyze whether JCV DNA can be detected in plasma or cerebrospinal fluid (CSF) in a large group of patients with NPSLE treated with immunomodulatory medication. 3 To investigate the distribution of ischemic stroke subtypes in SLE patients, classified according the TOAST system (Trial of Org in Acute stroke Treatment) and the association of stroke subtypes with the SLE risk genotypes; STAT4 and HLA-DRB1. 4 To determine the prevalence and classify seizures and epilepsy among patients with SLE and investigate the relationship between epilepsy and other manifestations of neuropsychiatric SLE. 20

35 4. MATERIALS AND METHODS 4.1. SUBJECTS AND STUDY DESIGN (I-IV) The patients included in our studies are mainly from a cohort, which now comprised about 440 SLE patients who fulfilled criteria for SLE (10, 11) and attending the Rheumatology Clinic at the Karolinska University Hospital. (Figure 3). During time of our studies, the rheumatologist added new patients to this Hospital-based cohort from 1996 to Studies I and II were cross-sectional and the SLE-patients were referred to the neurology clinic for clinical investigation because of NPSLE symptoms. In this thesis we utilized blood and cerebrospinal fluid that were kept frozen at -70 C in our in-house biobank. MRI and/or CT scans of the brain, EEG and other neurophysiological investigations were performed depending on the clinical presentation. All the patients in study IV were from this cohort. In study III the patients were included from the cohorts in Karolinska Solna (N=380), Uppsala (N=131) and from Lund (N=154). Studies III and IV had a retrospective design. The matched control samples used in studies I and II were from non-inflammatory neurological patients, mostly tension headache and in study I samples from relapsing remitting Multiple sclerosis (RRMS) patients were included. Figure 3. Study design 21

36 All studies included were approved by the regional Ethics Committee and written informed consent was obtained from all study participants. Paper I Twenty-eight patients with neurological manifestations of SLE were included. APRIL and BAFF in paired plasma and CSF samples from NPSLE patients were quantified using a commercial ELISA kit, thirteen RRMS patients and seventeen OND patients acting as controls. Quantitative PCR was performed for APRIL and BAFF mrna respectively for CSF and PB. The Fatigue Severity Scale (FSS) was used to measure the degree of fatigue. Paper II Plasma and/or CSF samples from 71 NPSLE patients and 58 control cases were analyzed. JCV DNA was analyzed using a quantitative PCR method. Paired CSF and plasma samples were obtained from 49 NPSLE patients and 44 of the control patients. At sampling ongoing medication were documented: corticosteroids (n=51), Hydroxychloroquine (n=22), Azathioprine (n=15), Methotrexate (n=3), Mycophenolate mofetil (n=3), Rituximab (n=3), Cyclosporine (n=1), Immunoglobulin (n=1), none for Cyclophosphamide, Chlorambucil or Reumacom. One of the patients had previously undergone autologous hematopoietic stem cell transplantation and plasmapheresis. Five patients had no treatment. Paper III Among 665 genotyped SLE patients from three large cohorts we identified 69 patients with stroke. The medical charts were reviewed and brain, cardiac and vascular imaging at the time of stroke was reinvestigated. The 56 ischemic stroke cases were possible to evaluate and categorize according to the TOAST subtypes. Evaluators were blinded to genotype. Association with STAT4 and HLA-DRB genotypes were explored. In the genetic comparisons the controls were either SLE patients free from previous ischemic cerebrovascular disease or general population controls. 22